Turbine



E. DUPONT May I, 1945.

TURBINE Filed Oct. 16. 1941 4 Shets-Sheet 1 May 1, 1945.

a DUPONT TURBINE Filed 001:. 16, 1941' 4 Sheets-Sheet 3 Patented May 1,1945 TURBINE Emile Dupont, Antibes, France; vested in the Alien PropertyCustodian Application October 16, 1941, Serial No. 415,306 r InSwitzerland June 24, 1941 2 Claims.-

This invention relates to a machine used for converting mechanicaliorceinto a pressure or conversely, where the manometric height measuring thepressure used or produced by a single wheel is distributed over aplurality of concentric blade rims suitably spaced and arranged on oneof the faces of the rotor, and over a plurality of concentric bladerimsarranged on one face of the stator and inserted into the ring spacesbetween the blade rims of the rotor, the flow of the fluid being acentrifugal flow when the machine converts mechanical force into apressure (compression and fluid pumps) and an inward radial flow whenthe machine converts pressure into mechanical force (gas turbine, steamand water turbines).

In the known machines of this kind the axial balancing is efiected bymeans of a chamber between the face of the rotor without blades and awall of the stator, and in which chamber the pressure is uniform andgenerally equal to the high pressure of the fluid. This is obtained bymeans of a passage provided in the rotor and insuring a communicationbetween the said balancing chamber and the high presure.

Thus, one of the faces of the rotor is submitted, for instance, to auniform pressure, while the other face is submitted to decreasing pres.-sures in front of each of the fixed and movable blade rims according tothe working of the machine as a compressor.

Accordingly, in these known machines the resulting pressure, that is tosay the difference between the pressures acting on the two faces of therotor, varies according to the distance of the point under considerationwith respect to the point where ambient atmospheric pressure exists.

The rotor is thus submitted in each of its points to resulting axialpressures the value of which varies and whichfor this reason do notproduce a good balancing effect. In every case, the balancing effect isperfect only for a predetermined particular value of the highest fluidpressure and the least variation of this pressure produces an axialthrust.

The present invention has for an object to avoid these drawbacks and toobtain a good axial balancing of the rotor in all the points of itssurface.

On the other hand, machines with concentric arate the said jet from theconvex face of the blade, which causes eddies which are prejudicial toefficiency.

Another object of the present invention is to avoid this drawback and toimprove the known machines so as to avoid any separation of the fluidjet from the convex face of the blade.

The improved machine which accomplishes the above mentioned objectspossesses the features set forth in the following description and more Vparticularly in the appended claims.

Machines made according to the invention are shown by way of example inthe appended drawings in which: 7

Figure l is an axial sectional view of the machine. A

Figure 2 is a partial axial sectional view' of the said machine.

Figure 3 is a diagram showing the axial pressures in-the machineaccording to the invention.

Figure 4 is on a larger scale a cross-sectional viewthrough the bladeswith the parallelograms of velocities.

Figure 5 is a partial axial cross-sectional view of modified form ofmachine according to the invention.

Figure 6 shows the lay-out of the blades of a machine according to theinvention.

The machine shown in Figures 1 to 4 has a driving shaft I. A rotatingwheel 2 is keyed on the driving shaft I; the wheel 2 is profiled in itsmiddle part according to a cone 3 the profile of which corresponds tothat of the gaseous je'. flow path on the intake side of the apparatus.

The rotating wheel 2 carries on one face 2 blade rims 4 4 4 4 themovable blades; the

profile of the said blades 4 4 4 4 (Figure 4) varies from one rim to theother and according to the characteristics of the apparatus (velocity,delivery) but they are always such that two successive blades of one andthe same rim form a curvilinear nozzlea The face 2 of the wheel which isnot provided .with blades carries'circular ribs 5 5 5 5 '5 5 5" adaptedfor forming the annular chambers C C and C The stator is provided with aslightly conical bracket 6; this bracket carries fixed blade rims 1 1 I1 l which are inserted between the movable blade rims 4 to 4 the fixedblade rim 1 being arranged externally with respect to the movable bladerim 4 Like the movable blades, the fixed blades are so formed that twosuccessive blades of one and the same rim form a curvilinear nozzle.

The stator is also provided with a bracket 8 which carries on one of itsfaces circular ribs 9 9, 9 9 9 9 9" forming with the circular ribs 5 to5" of the rotating wheel 2, chambers I0 I0 I0 I0 I0 I0, I 0", In, whichare connected together by conduits of small section H II, II, II. II,II. Aconduit I2 is provided between the fixed blade rim 1 and themovable bladerim 4 the said conduit connects the chamber I with theface2 of the wheel 2.

The conduits II and I2 are formed by the necessary clearances betweenthe fixed and movable parts.

Counterpressure chambers 1 1 1 and. I are provided between the fixedblade rims l 1 1 and I and the face 2 of the wheel 2.

Passages I1 I1 I1 11* are provided in the 'wheel 2 and connect chambers1 1 1, 1 and chambers I0 I0 and It.

Counter-pressure chambers 35 35 35 35" are provided between the coverring 3B 3B 36?, 38" of each movable blade rim and the bracket 6 of thestator.

The fluid is admitted through a conduit l3 provided in the stator andopening into an admission manifold it; the fluid leaving the blades isdelivered into an outlet manifold I5 and flows out through openings itwhich are provided in this manifold lb.

The above described machine works as a compressor in the followingmanner:

The rotor rotates in the direction of the arrow 1 (Figure 4); a movableblade rim 8 and the fixed blade rims l and l which are directly on bothsides of the former will now be considered. The fixed blades of the rim1 which are so inclined as to insure the correct-inlet of the fluid intothe movable blades form a distributor. .The fixed blades of the rim 1act as a diffusor for the movable blade rim 4 and as a distributor forthe movable blade rim t 1 Thus, each movable blade rim 4 to 4 producesan independent compression as well as each fixed blade rim 7 to 1 sothat successive compression stages are formed seriatim. 1

The gaseous fluid which is thus drawn in through the axial conduit isprogressively com- (30S (11*- UoVu 005 do) where P is'the weight offluid treated per second,

9 the acceleration of the gravity,

U1 the driving velocity on the periphery of the movable blade rim,

.Vi the absolute velocity of the fluid leaving the movable blade rim,

al the angle formed by both these velocities,

U0 the driving velocity at the inlet to the movable blade rim,

Vo the absolute velocity of the fluid. at this inlet,

and I do the angle formed by these two velocities.

The profile of the movable blades is selected so as to give to the anglea0 a, value of more than 90; accordingly the term UoVo cos so hasa'positive value and is added to the term Ulvl cos G1 in the above givenformula, thus giving the power W.

The slight inclination of the movable blade' manner: the passages I1 I1I1 I14 connect the annular chambers I0 Hi I0 Ill with the correspondingfixed blade rims T i 1 and i of the face 2 of the rotor and thus producein the said chambers pressures which are equa1 to the pressures existingin the said fixed blade rims and acting on the face 2 of the rotor. Atthese points of the rotor the pressure is thus the same on the face 2and onthe face 2 thus producing the axial balancing effect.

On the other hand, the passages I i connect the chambers W to ittogether so that in the chamber N1 for instance, a pressure isestablished which is intermediate to the pressures existing in thechambers l0 and I0 between which the said chamber is inserted. Thisintermediate pressure is the same as the pressure exerted by the chamber35 on the cover ring 36 of the movable blade rim 4 This pressure isintermediate between the pressures existing in the fixed blade rims Iand 1 between which the movable blade rims 4 are inserted; in a likemanner the pressure in the chambers 35 35 35 corresponding to themovable blade ribs 4 4 and 4 corresponds to an equivalent pressure inthe chambers I0 I0 I0 opposite to the said movable blade rims.

Thus the pressures are equal in all points on each face of the rotor sothat the axial balancing is attained in a perfect manner.

This regular distribution of the balancing effect is clearly shown bythe diagram of Figure 3; to each pressure P1 Pn acting on the face 2 ofthe rotor whichis provided with movable blades corresponds an equalcounter-pressure of contrary direction P1 Pn acting on the opposite face2 of the said rotor; thus an axial balancing effect is obtained in eachpoint of the surface of the rotor.

Numerous changes can be made in the machine shown in Figures 1 to 3without departing from the spirit and scope of the invention.

Figure 5 more particularly shows a machine according to anothermodification of the invention. The rotor 2 of this machine is providedon its face 2 with annular chambers I8 l8 I811 acting as balancingchambers. These annular balancing chambers are connected together bypassages I9 I9, the whole of the chambers I8 and of the passages I9forming a labyrinth in which the fluid velocity acquired in one passageI9 is reduced to zero in the following chamber l8.

-0n the other hand, in the cover rings 21 21 of the movable blade rims,hollows are provided which form annular balancing chambers 22 22 22 and24 24 24 with the wall 25 of the stator, the chambers 24' beingconnected together by the passages 23 23 23 and the chambers 22 beingconnected together by the passages 25 25 25 The cover rings '28 of thefixed blade rims are also provided with cavities forming with the wall2' of the rotor annular balancing chambers 20', 20 connected together bypassages 2P, 2|, 2|.

Passages 26 2G, vided in the wheel 2 and connect both faces of the wheeltogether in the place of the balancing chambers 20 and I8, 20 and I8.Certain of these passages 28 are always arranged between the centre ofthe rotor and the-first movable blade rim in order to connect the centreof the rotor with the intake side of the machine, and must have asufflcient cross-sectional area for leading the fluid leakage from theface 2 towards the face 2 In the annular chambers, for instance 20 20",20 a flow of fluid will establish itself through the passages Il 21", 2|so that the pressure existing in these chambers will be the same as thepressure existing in the blade rim 1. In short, this device establishesa pressure in the space between the cover ring of the blades and thestator in the case of a movable blade rim, or between the blade coverring and the rotor in the case of a fixed blade rim, which pressure isequal, on the one hand, to the pressure existing in the blade rim underconsideration and, on the other hand, to the pressure existing in thecorresponding chambers of the face 2% of the rotor, thus producing anaxial balancing effect in all the points of the rotor.

This machine ofiers variousadvantages and more particularly thefollowing ones:

. in any number are pro- (a) A perfect balancing effect is obtained ifthe member of the chambers and the dimensions of the latter are the samefor each face of the wheel;

(b) The tightness between two successive blade rims is increased, sothat leakage is reduced and the efficiency increased. I

For working as a compressor the machine of the invention avoids thedrawbacks of the known blade rims by providing a particular form ofblade rims (Figure 6).

The blades of these fixed and movable blade rims have an increasedthickness 31 from the region of their bend up to their extremities;accordingly, the fluid Jet remains always in contact with the convexsurface 38 of the blade and thus the above mentioned separating effectdue to the centrifugal'force is avoided.

The blades are also provided on their outlet faces with a cylindricalsurface 39 which is so formed that the fluid jet 40 leaving the frontblade rim leaves a partial vacuum zone 4| in the following blade rim.

The said blade rims offer the following advantages:

(a) The eiliciency of the curvilinear nozzle front of the rear edge ofthe fixed blade (position shown in Figure 6) Then, during the time whichthe movable blade requires for travelling along the segment e, itshollow face receives no fluid. Thus, the pressure drops along thishollow face due to the inertia of the fluid which it contained and whichpossessed a certain velocity, as well as due to the friction of the jetflowwhich flows along the convex face of the preceding blade.

When the hollow face of the movable blade comes in front of the point B(front edge of the fixed blade) the pressure existing along this hollowface is nearer to that which exists in B.

The tendency of the fluid jet to flow back which periodically occurs inblade rims made according to the methods heretofore employed, each timewhen a movable blade passes in front of a fixed blade, is reduced to alow value or even to zero in the case of my invention. Eddies are thusless violent and the internal eiflciency is therefore improved.

My invention covers this particular form of structure of the bladesirrespective of the kind of turbine or compressor in which the saidblades are used.

I claim:

1. In a machine for converting the pressure of a fluid into mechanicalforce or conversely: a rotor formed of a disc carrying on one of itsfaces concentric suitably spaced blade rims, a stator also carryingconcentric blade rims inserted into the annular spaces between the bladerims of the said rotor, cover rings for the fixed and movable bladerims, means for radially conducting the fluidinto the concentric bladerims of the said stator and rotor, annular'chambers provided on the faceof the rotor which is not provided with blade rims, each annular chamberbeing ar-' ranged in front of a blade ,rim, annular balancing chambersprovided between the cover rings of the fixed blade rims and the rotor,onthe one hand, and the movable blade rims and the stator on the otherhand, the said annular balancing chambers simultaneously insuringtightness beformed of two successive blades of one and the same blade.rim is increased since the fluid let flow path is not separated from theconvex surface 38, which avoids the formation of eddies in the said J6(-b) The action of the centrifugal force ina curvilinear blade rim hasfor its effect that at A (Figure 6) the pressure is considerably higherthan at B. v

Thus as the-hollow face of a movableiblade is moving in the direction ofthe arrow and receives fluid of a higher pressure, their the edge ofthis movable blade is ata given instant positioned in tween thesuccessive blade rims and the balancing of the rotor and of the coverrings of the fixed and movable blade rims and passages for conductingthe fluid to the annular chambers.

2. In a machine forconverting the pressure of a fluid into mechanicalforce or conversely: a rotor formed of a disc carrying on one of itsfaces concentric suitably spaced blade rims, a stator also carryingconcentric blade rims inserted into the annular spaces between the bladerims of the said rotor, the successive fixed or movable blades leavingbetween themselves spaces'in form of nozzles, the profile of the movableblades being such that the direction of movement of the fluid at theinlet is reversed with respect to the direction of the movement of theblades, means for radially leading the fluid into the concentric bladeprovided with blade rims, each annular chamber being arranged in frontof a blade rim in order to insure an axial balancing effect in everypoint of the surface of the rotor and passages for conducting the fluidto the annular chambers.

Elm-E DUPON'I T.

